Having worked as a Network Administrator for a Cable company one of my tasks was to give the FBI customer info as part of a subpeana. More ofthen than not the address that the
FBI showed up at was the residence of clueless family or an elderly couple, whom were obviously distressed to find the FBI knocking on their door.

A hacker will steal your information such as account and credit card data. And they may not use that stolen information for months. Something a bit scarier however is that once they
are in your network they can use if for all sorts of nefarious activities which all traces right back to you.